During road paving, the surface to be paved must be dry to in accordance with Department of Transportation (DOT) requirements before paving can commence. A machine that will allow expedited drying saves road paving crews significant time and money. As an example, roads crews arriving early morning before sunrise often encounter high levels of dew on the surface to be paved. Typically they would be on hold until the sun had risen and provided sufficient heat for drying. This type of delay is very problematic because many road projects are on a very short time schedule in order to keep traffic moving. In addition, it is very costly to the paving companies to have entire crews standing around waiting for the sunrise to achieve required DOT levels of dryness.
Another challenge road paving and maintenance crews face is short rain showers. A quick five-minute rain shower can stop a road paving crew for over an entire day or longer. Also, trucks are continuously bringing asphalt and materials to the job site; if the project is delayed due to rain these materials are no longer usable and must be disposed.
Road drying machines of the prior art, sometimes referred to as “jet dryers,” use a turbine engine exhaust which exhibits several problems. The shortcomings faced include: 1) inability to remove moisture from the air used for drying; 2) inability to reduce or minimize the addition of spent hydrocarbons into the drying air stream; 3) tendency to exceeding the DOT maximum allowable temperature for the road surface; 4) noise levels are too high to operate close to personnel or nearby road traffic; 5) the air stream cannot be directed to the road surface whereby it prevents using the machine in conjested traffic areas where most paving is done; 6) the jet engine is susceptible to failure due to the intake of foreign particles, and the process by nature is typically operated in a very dust filled environment due to the close proximity of mechanical brooms; 7) jet engines require frequent maintenance and construction personnel are not able to maintain or repair jet engines without outside help; and 8) jet dryers are prohibitively expensive to operate for a road drying application. Drying or conditioning the air prior to release onto the surface is important to increase the water-holding capacity of the air and thus make the drying machine faster and more efficient. Reducing the hydrocarbons resulting from combustion is important because hydrocarbons contain, and rapidly collect, moisture which reduces drying capability and adds a residual film on the road surface that is not desirable. Air delivery temperatures should not exceed 300 degrees Fahrenheit for extended periods of time, as this is a temperature acceptable in DOT paving operations.
Finally, road drying machines of the prior art may be incapable of nozzle adjustment to fit road surfaces having different widths, or to accommodate various curb and median arrangements.